I am a multiple of 6 between 70 and 80. My ones digit is 6 when you remove 6.
Start skip counting by 6 until 6 x 6 so it will be within 70 - 80 when you multiply it again.
6 x 2 = 12
6 x 3 = 18
6 x 4 = 24
6 x 5 = 30
6 x 6 = 36
Now that we stopped, we multiply it by 2.
36 x 2 = 72
72 is within 70 - 80, so it is possible. Now let's check for other possible answers.
72 - 6 = 66, but it is not within 70 - 80, so cross it out.
72 + 6 = 78, so it is possible.
But how do we know if it is 72 or 78? Both are even because 6 is even. Now let's find out.
Well, my ones digit! Taken away from the ones digit, it becomes 70. But that's not a multiple of 6! And it is not within 70 - 80.
Well actually, we all get remainder 0 even when we divide them into 2, they are really even. Incase you thougt of it.
But when you remove six from it, let's try:
72 - 6 = 66, so it is possible.
78 - 6 = 72, so it is wrong.
The answer is 72.
